Machine for forming piston ring spacer-expanders from strip stock

ABSTRACT

A machine for making spacer-expanders for piston oil rings of the type described in United States Pat. No. 3,477,732. The machine comprises a punch press having a plurality of stations through which strip stock is fed progressively in accurately predetermined increments, the strip stock being worked between dies at each station to transform the strip stock into completed rings. The press includes one or more punching stations where the strip stock is pierced and blanked, one or more forming stations where the pierced and notched strip is bent to form the spring legs of the spacer-expander and then curled into a channel-shaped cross-section, a coiling station where the channel-shaped stock is fashioned into a coil, and a cut-off station where each coil is sheared from the strip to form the semi-finished ring. The press also includes a special transfer apparatus for transferring the semi-finished ring to a final work station wherein the end joints are trimmed and formed to final configuration, after which the finished rings are loaded automatically in stacked relation on a cylindrical mandril.

United States Patent 1 Overway I MACHINE FOR FORMING PISTON RING SPACER-EXPANDERS FROM STRIP STOCK Primary ExaminerCharles W. Lanham Assistant ExaminerR. M. Rogers Attorney-Arthllr Raisch, John M. Kisselle, Robert A. Choate et al.

[ 1 June 19, 1973 57 ABSTRACT A machine for making spacer-expanders for piston oil rings of the type described in United States Pat. No. 3,477,732. The machine comprises a punch press having a plurality of stations through which strip stock is fed progressively in accurately predetermined increments, the strip stock being worked between dies at each station to transform the strip stock into completed rings. The press includes one or more punching stations where the strip stock is pierced and blanked, one or more forming stations where the pierced and notched strip is bent to form the spring legs of the spacerexpander and then curled into a channel-shaped crosssection, a coiling station where the channel-shaped stock is fashioned into a coil, and a cut-off station where each coil is sheared from the strip to form the semi-finished ring. The press also includes a special transfer apparatus for transferring the semi-finished ring to a final work station wherein the end joints are trimmed and formed to final configuration, after which the finished rings are loaded automatically in stacked relation on a cylindrical mandril.

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PAIENIE JUN 1 9 ma sum mar 11 IWN Pa 202.3% Mn E V W @N U Qhwmv m8. vmn w mw mm MACHINE FOR FORMING PISTON RING SPACER-EXPANDERS FROM STRIP STOCK rings of the type commonly located between thin metallic rails in the oil groove of a piston of an internal combustion engine.

An object of this invention is to enable production of such rings accurately, economically and at a high rate.

Another object is to provide an improved machine capable of automatically forming spacer-expanders of the type disclosed in United States Pat. No. 3,477,732, particularly in connection with FIGS. 1-5 inclusive and FIGS. 15 and 16 thereof.

A further object is to provide an improved machine capable of performing the improved method of making such a spacer-expander as disclosed in a copending application of Frank G. Warrick, Ser. No. 39,264, filed May 21, 1970, now US. Pat. No. 3,633,260, entitled Method of Forming a Spacer-Exapnder, and assigned to the assignee of the present application.

A further object is to provide an improved machine of the above character utilizing certain components and functions of the machine disclosed and claimed in U. S. Pat. No. 2,925,847, assigned to the assignee of the present application, and to improve upon said prior machine.

Other objects, features and advantages of the apparatus of this invention will become apparent from the following detailed description and accompanying drawings wherein:

FIG. 1 is a fragmentary front elevational view of an exemplary but preferred embodiment of the machine of the present invention.

FIGS. 2, 3 and 4 are fragmentary plan views of the strip stock respectively showing the operations performed thereon at the first, second and third punching, blanking and bending stations of the machine.

FIG. 5 is a fragmentary perspective view of the strip stock illustrating the feet and leg bending operations performed thereon successively at stations Nos. 3 and 4 respectively.

FIG. 6 is a fragmentary view-partially in vertical elevation and partially in vertical center section through the strip guide infeeding mechanism and leg bending dies of station No. 4.

FIGS. 7 and 8 are fragmentary and elevational and part verticalsectional views taken generally on the line 7-7 of FIG. 6 and respectivelyillustrating the dies of station No. 4 in their open and closed positions.

FIG. 9 is a fragmentary plan view of the strip infeed guide of station No. 4.

FIGS. 10 and 11 are fragmentary enlarged views of the dies as viewed in FIGS. 7 and 8 respectively.

FIG. 12 is a fragmentary front elevational view showing a portion of the die structure shown in FIG. 6 but enlarged thereover and with the dies in closed position.

FIG. 13 is a vertical sectional view taken on the line l3l3 of FIG. 5 but enlarged thereover.

FIG. 14 is a fragmentary front elevational view of the dies of station No. 5 shown partially in vertical center section and with the dies closed.

FIG. 15 is a fragmentary end elevational view of the entrance to station No. 5 taken on the line 15-15 of FIG. 14.

FIG. 16 is a fragmentary vertical sectional view taken on the line l616 of FIG. 21 and illustrating the progressive strut bending operation being simultaneously performed by the last seven of the 10 punches and associated dies of station No. 5.

FIGS. l7, l8, 19, and 21 are fragmentary vertical sectional views taken respectively on the line 1717 of FIG. 14 and lines 18-18, 1919,. 20-20 and 21-2l of FIG. 16.

FIG. 22 is a vertical sectional view taken on the line 2222 of FIG. 16 illustrating the finished crosssectional contour of the strip as it emerges from station No. 5.

FIG. 23 is a fragmentary horizontal sectional view taken on the line 2323 of FIG. 14 illustrating the stationary stripper components in the lower die shoe of station No. 5.

FIG. 24 is a fragmentary horizontal plan view of a portion of the structure shown in FIG. 23 with the stationary stripper parts removed to better illustrate the underlying movable stripper and. stationary forming dies in the lower die shoe.

FIGS. 25, 26 and 27 are fragmentary vertical sectional views taken respectively on the lines 25-25, 26--'26 and 27-27 of FIG. 14.

FIG. 28 is a fragmentary perspective view of the lefthand stripper plate of station No. 5 shown by itself.

FIG. 29 is a fragmentary front elevational view of a portion of the induction heating coil of station No. 6 and also illustrating the coiling and! cut-off apparatus of station No. 7 of the machine.

FIG. 30 is a fragmentary front elevational view of the components of station No. 7 with the guide shield and blow-off air tube parts removed to better illustrate details.

FIG. 31 is a fragmentary end elevational view of the entrance guide of station No. 7 looking in the direction of arrow 31 in FIG. 30.

FIG. 32 is a fragmentary vertical sectional view taken on the line 32-32 of FIG. 30.

FIG. 33 is a fragmentary vertical sectional view taken on the line 3333 of FIG. 30.

FIG. 34 is a fragmentary plan view of the strip stock after it has been severed in the cut-off operation of station No. 7.

FIG. 35 is a fragmentary front elevational view of a portion of station No. 7 illustrating the strip coiling anvil and associated bending pad in the open position thereof.

FIG. 36 is a fragmentary end elevational view of actuating linkage in station No. 7 as viewed on the line 36-36 of FIG. 30.

FIG. 37 is a fragmentary front elevational view of the apparatus of stations Nos. 8 and 9 of the machine.

FIG. 38 is a fragmentary front elevational view of a portion of the station No. 8 apparatus shown in FIG. 37 but illustrating the pusher members in closed position embracing the entrance cone of this station.

FIG. 39 is a side elevational view of the apparatus of station Nos. 8 and 9.

FIG. 40 is a fragmentary horizontal sectional view taken on the line 40-40 of FIG. 37 illustrating a portion of the apparatus of station No. 9.

FIG. 41 is a horizontal sectional view taken on the line 41-41 of FIG. 37.

FIG. 42 is a horizontal sectional view taken on the line 4242 of FIG. 37.

FIG. 43 is a fragmentary horizontal section of the shot pin and slide parts of FIG. 42 but with the shot pin shown in engaged position with the slide.

FIG. 44 is a fragmentary side elevational view illustrating the punch, clamp and die components of station No. 8, FIG. 44 being partially taken in vertical center section and enlarged over FIG. 39.

FIG. 45 is a fragmentary vertical sectional view taken on the line 45 45 of FIG. 44.

FIG. 46 is a fragmentary horizontal sectional view taken on the line 46-46 of FIG. 44 but greatly enlarged thereover.

FIG. 47 is a fragmentary vertical sectional view taken on the line 47-47 of FIG. 46.

FIG. 48 is a fragmentary plan view of a portion of the parts shown in FIG. 46 but with their position changed to illustrate the joint trimming and initial bending action.

FIG. 49 is a view similar to FIG. 48 showing the parts at the completion of the trim and bending stroke.

FIG. 50 is a fragmentary side elevational view of the left-hand clamp member shown in FIGS. 46, 48 and 49.

FIG. 51 is a fragmentary side elevational view of the right-hand shearing and bending punch shown in FIGS. 46, 48 and 49.

FIG. 52 is an end elevational view of the left-hand forming die shown in FIGS. 46, 48 and 49.

FIG. 53 is a fragmentary perspective view of one end of the spacer-expander illustrating the end joints thereof after being trimmed and bent in station Noi 8.

For purposes of facilitating description and not by way of limitation, the machine 100 of the present invention is illustrated with the proper dies for forming the piston ring spacer-expander illustrated in the aforementioned Warrick U.S. Pat. No. 3,477,732, particularly the spacer-expander 58 shown and described in conjunction with FIGS. 1-5 inclusive thereof and with the end joint construction shown and described in conjunction with FIGS. 14-16 inclusive thereof, this patent being incorporated herein by reference and hence spacer-expander 58 thereof not being described herein.

GENERAL ARRANGEMENT Machine 100 of the present invention is shown substantially in its entirety in FIG. 1 and generally consists ofa punch press similar in part to that shown, described and claimed in the aforementioned Burns et al. U.S. Pat. No. 2,925,847, which is incorporated herein by reference for a detailed disclosure of certain portions of the machine identified in more detail hereinafter.

Machine has a base 102 which supports a frame 104 and a motor 106 on frame 104 which drives a flywheel 108 through a belt 110. Flywheel 108 is connected by a clutch 112 with the crankshaft 114 of the press. Clutch 112 is of the positive drive, electric throw-out type. Shaft 114 is journalled on the frame of the machine in bearings 1 16. A pair of magnetic brakes 118 are arranged around shaft 114 and when electrically energized operate to sieze shaft 114 when the circuit to the brake is closed. Shaft 114 has three crank portions to which the upper ends of connecting rods 120, 122 and 124 are individually pivotally connected. Rods 120, 122 and 124 are connected respectively at their lower ends to associated rams 126, 128 and 130 which are guided for vertical reciprocating movement on frame 104 in ways formed in three sets of guide plates 132, 133 and 134 respectively.

As set forth in more detail hereinafter, ram 126 operates a piercing die assembly 136 of station No. 1 anda blanking and notching die assembly 138 of the station No. 2. Ram 128 operates a foot bending and joint notching die assembly 140 of station No. 3 and a leg bending die assembly 142 of station No. 4. Ram 130 operates a strut bending and strip curling die assembly 144 of station No. 5 and, also, through a linkage 804, operates a coiling and cut-off die assembly 146 of station No. 7. The end joint trimming and bending die assembly 148 of station No. 8 is powered by pneumatic rams synchronized with the operation of the press by a suitable counting and control mechanism as described in more detail hereinafter.

The end of shaft 114 remote from flywheel 108 carries a disc 150 to which a link 152 is eccentrically connected for driving a strip feeder 154 through a bell crank 156. A suitable commercially available magnetic pick-up assembly is provided for counting revolu tions of shaft 114 to develop one signal per each vertical reciprocation of the rams 126, 128 and 130 through their simultaneous mechanically synchronized working strokes. Pick-up 160 has a rotating part 162 secured to shaft 114 for rotation therewith and a stationary part 164 secured to the stationary structure of the end bearing 116. Pick-up 160 provides the input signal to a suitable counter control (not shown), such as that sold under the trademark DYNAPAR made by the Louis Allis Division of Litton Industries at the Digital Center in Gurnee, Ill. and identified as a Digital Process Controller Type 5X2-58-X-l. This controller operates through the signals derived from pick-up 160 to initiate the cut-off operation as well as the air blast at station No. 7. This occurs in response to an output signal developed by storing the number of counts in the digital memory of the controller corresponding to the number of increments of advance of the strip being worked in machine 100 required to pass a given length spacerexpander through the coiling die of station No. 7. Also, this control further provides an output signal for actuating the pusher fingers of station No. 8 after allowing a time delay (corresponding to a given number of counts) for the severed spacer-expander to drop onto the nose cone of station No. 8. The remaining motions in stations Nos. 8 and 9 are controlled by conventional limit switches and solenoid valve circuitry (not shown) associated with the moving parts of this station as described in more detail hereinafter.

The counter control is also adapted to generate a control signal for causing a transverse shuttle motion of die assemblies 136, 138 and 140 of stations Nos. 1, 2 and 3 as an end joint zone of the strip stock being fed therethrough comes into successive registry with the respective die assemblies, as set forth in more detail hereinafter.

In general, the operation of machine 100 is as follows:

Steel strip material 170, preferably stainless steel of the A.I.S.l. 301 type, is pulled from a coil 172 by feeder 154 and pushed with an intermittent advance and then 

1. In a press for performing a bending operation repetitively on a length of strip stock, the combination comprising a die assembly having a lower shoe stationarily supported adjacent the path of feed of said strip, an upper shoe disposed in alignment with said lower shoe and on the opposite side of the path of strip feed from said dower shoe, punch and die means mounted in said shoes cooperable to perform a bending operation on said strip in response to closing movement of said upper shoe relative to said lower shoe, means for reciprocating said upper shoe through said closing and opening movement, means forming a guideway for guiding the strip stock through the die assembly, a feed mechanism for feeding the strip stock through said guideway with a step-by-step movement timed with the stroke of the punch and die means, and stripper means mounted between said shoes and forming a portion of said guideway, spring means between said stripper means and said lower shoe biasing said stripper means toward said upper shoe, stop means for limiting movement of said stripper means toward said upper shoe, and means on said stripper means cooperable with said punch means on said upper shoe whereby said strip is first clamped between said stripper means and said upper shoe punch means during closing movement of said upper shoe and then said stripper means moves with said upper shoe toward said lower shoe to retain said strip in clamped relation during a last portion of the closing movement of said die assembly to perform said bending operation on said strip.
 2. The operation as set forth in claim 1 wherein said guide means comprises an arm pivotally mounted for swinging movement about an axis perpendicular tO the direction of strip feed and located in advance of said die assembly, said arm defining a guideway therethrough for said strip, said arm having a free end resting on the side of said strip opposite said lower shoe between said stripper means and said upper shoe, and means biasing said arm to urge said free end of said arm toward said stripper means into yieldable sliding engagement with said strip.
 3. In a press for performing a series of operations repetitively on a length of long, narrow and thin strip stock having initially a flat contour, the combination comprising a feed mechanism for feeding said stock in the direction of its lengthwise dimension, a first station including means for performing an operation on said strip stock while the strip retains its generally flat contour, a second station located in line with the path of travel of said strip stock downstream of said first station, said second station having punch and die means mounted opposite one another on opposite sides of the path of travel of said strip stock and movable relative to one another in the direction of the thickness of said strip for performing a second operation on said strip stock without substantially altering its width dimension, a third station downstream of said second station in alignment with said path of travel of said strip stock and including means movable in said thickness direction for imparting a cross-sectional configuration to said strip stock wherein said stock is bent about at least one longitudinally extending bend line and its overall width reduced and guideway comprising angle means in said first, second and third stations adapted to slidably confine said strip stock against movement in the direction of its width, said feed mechanism being located upstream of said first station and operable to grip and push said strip stock in its flat state lengthwise through said guideway, said guide means of said first station being stationary and said guide means of said second and third stations including platform means movable in said thickness direction, said platform means of guide means of said second station including a pivoted arm pivotable about an axis parallel to said strip width dimension and located adjacent the outlet of said guide means of said first station.
 4. The press as set forth in claim 3 wherein said platform means of said second station includes a stripper positioned between the end of said arm remote from its pivot axis and the inlet of said guide means of said third station and movable in tracking relation to the movement of the remote end of said arm.
 5. The press as set forth in claim 4 wherein said second station guide means includes a blade pivoted to said arm extending downstream of said strip therefrom and having a free end resting on the side of said strip stock remote from said platform means, said blade extending through said second station.
 6. The press as set forth in claim 5 wherein said third station guide means has an inlet passage with a second stripper therein movable in the direction of said strip thickness in unison with the movement of said first-mentioned stripper in said thickness direction.
 7. The press as set forth in claim 6 wherein said outlet os said guide means of said third station comprises a stationary passageway having a dimension in said thickness direction operable to permit movement of said strip with said second stripper. 